Articles & Insights

R-22 is being phased out, but thousands of R-22 systems are still running across Southern Africa. A lubrication engineer's guide to keeping them healthy, choosing a retrofit refrigerant, and changing oil without leaving an immiscible residue behind.

In an oil-injected screw compressor, oil seals the rotors, carries away heat of compression and lubricates the bearings. How the oil circuit works, where it goes wrong, and how oil analysis turns the lubricant into a condition-monitoring tool.

CO2 is a natural refrigerant with a GWP of 1, but it asks more of the compressor oil than any HFC. Why R-744 is different, what the oil must do in subcritical cascade and booster systems, and where RF POE 85 CO2 fits.

Polyolester oils make HFC and HFO refrigeration possible, but they absorb water, and water turns esters into acids. The chemistry, the warning signs and a practical handling protocol that keeps POE systems dry.

The viscosity printed on the drum is measured with no refrigerant present. At the bearing, dissolved refrigerant can reduce it dramatically. How to select a grade on working viscosity, not label viscosity.

Oil that does not dissolve in the refrigerant does not come back to the compressor. How mineral, alkylbenzene, POE, PAG and PAO oils behave with HCFC, HFC, HFO and CO2 refrigerants, and how to read a miscibility table.

In a refrigeration compressor the oil lubricates, seals, cools and travels the whole circuit with the refrigerant. Choosing it is an engineering decision, and that is how AA Lubricants approaches every application.